Question

calculate the volume of 0.850 - m naoh solution needed to completely neutralize 63.1 ml of a 0.260 - m solution of the monoprotic acid hbr.

Explanation:

Step1: Write the balanced chemical equation

$HBr + NaOH=NaBr + H_2O$
The mole - ratio of $HBr$ to $NaOH$ is $1:1$.

Step2: Calculate the moles of $HBr$

Use the formula $n = M\times V$, where $M$ is the molarity and $V$ is the volume in liters.
$V_{HBr}=63.1\ mL = 0.0631\ L$, $M_{HBr}=0.260\ M$
$n_{HBr}=M_{HBr}\times V_{HBr}=0.260\ mol/L\times0.0631\ L = 0.016406\ mol$

Step3: Determine the moles of $NaOH$

Since the mole - ratio of $HBr$ to $NaOH$ is $1:1$, $n_{NaOH}=n_{HBr}=0.016406\ mol$

Step4: Calculate the volume of $NaOH$

Use the formula $V=\frac{n}{M}$, where $n$ is the number of moles and $M$ is the molarity.
$M_{NaOH}=0.850\ M$, $n_{NaOH}=0.016406\ mol$
$V_{NaOH}=\frac{n_{NaOH}}{M_{NaOH}}=\frac{0.016406\ mol}{0.850\ mol/L}=0.0193\ L$
Convert to milliliters: $V_{NaOH}=0.0193\ L\times1000\ mL/L = 19.3\ mL$

Answer:

$19.3\ mL$